Longstem Tubestock

In the 1950’s when the seriousness of the damage to Australia’s river systems was becoming properly understood by authorities, funding was initiated to carry out urgently needed engineering and riparian revegetation work. These initiatives have now become ongoing programs of repair and restoration.Although native trees were used in the revegetation of the stream environs, greater use was made of the willow because it lent itself to deep planting as a hardwood cutting. When planted in moist soil the willow cutting quickly develops roots along the submerged stem. This supports rapid growth and a strong resistance to being washed away in flood conditions.Although the willow proved particularly effective in stabilising the stream banks, it ran counter to the desirability of restoring the original native stream bank ecology which had been destroyed in earlier clearing of trees and under-story plants alongrivers and streams.The desire to find an alternative to the willow, initially because it was environmentally out of place and ecologically damaging, had been heightened in recent years by the increasing tendency for willows to extensively propagate from seed in the stream beds and banks. In some river systems this had reached serious proportions and the rapidly developing population of willows threatened the basic integrity of the river channels.At the Australian National Stream Management Conference, it was unanimously adopted by river management authorities from across the country, that willows should no longer be considered as a tool in stream management programs.As a result many willow species have now being declared noxious and therefore are no longer an option, even if their violation of the native ecology could be tolerated.However this presented a problem as it is not possible to plant Australian native trees as large hardwood cuttings, as is done with willows. Historically, when native trees were used in riparian revegetation programs, it was generally carried out using tubestock trees, i.e. plants grown for about six to seven months in 50mm x 130mm square plastic forestry tubes. Trees grown in this manner would, at the time of planting, be in the order of fifteen centimetres long.However experience had shown that conventional tubestock trees are vulnerable to wash-away from floods and are also subject to heavy losses as a result of the top soil drying out in hot dry periods. This then created a serious dilemma, how to reliably replace willow plantings with appropriate native species.The answer turned out to be a new and innovative method of growing native trees that would replicate all the advantages previously attributed to willows.Over a number of years Bill Hicks, an electrical engineer, with a lifelong interest in the ecology and in the propagation of Australian native plants, had been independently working on developing a system of growing and planting native trees which would replicate all the favourable characteristics of willows, especially their ability to be deeply planted. This would contrast to the conventional surface planting procedures employed with standard tubestock. He also had in mind that any development with that aim might also result in a more effective and productive use of tube grown plants in a wide range of tree planting programs.

“THE SYSTEM IS NOW KNOWN AS LONGSTEM TUBESTOCK”

Longstem tubestock is a tree or under-story shrub grown in the same standard 50mm square tree tube used in the growing of standard tubestock. But in the case of longstem tubestock the plant is grown to a length similar to that of an average willow cutting, a length of one metre, or more. Being developed within the dimensions of the 50mm tube, the plant root-ball is small enough to be inserted into a deep hole not dissimilar to that provided for the deep planting of a willow cutting. About three quarters of the length of the plant is placed below the soil surface.In achieving this result two traditional, and long held horticultural principles have been overturned (1) that the growing of an advanced plant in a restricted container would result in damaging root deformation and (2) that planting a rooted plant deeply below the soil surface level would result in the development of tissue diseases to the submerged stem of the plant. This would either destroy the plant or degrade its development.Both of these assertions have been proven incorrect in the longstem tubestock system. By developing a special fertiliser regime, with particular emphasis on trace elements and elevated levels of NKP, the longstem plants grow to an extended length within the small container while maintaining an ideal, undistorted, root structure. Additionally it has been found that, when planted, the deeply immersed plant stems are totally undamaged by fungal diseases. They were in fact found to develop a strong adventitious root system between the original deeply planted root ball and the soil surface. These roots provide additional nutrient access and structural support for the growing plant.Becoming aware of the longstem system, the Hunter Catchment Management Trust and the New South Wales Department of Land and Water Conservation decided to adopt the technology for their major revegetation programs in the New South Wales, Hunter Valley.As a consequence of this decision hundreds of thousands of native longstem trees were planted along the Hunter River and its subsidiaries. These plantings achieved outstanding results in both growth and reliability and set in train the restoration of the original native ecology throughout the Hunter region. Following the success in the Hunter, longstem tubestock is now being widely used across Australia, not only for riparian plantings, but a wide range of revegetation opportunities which have been opened up by taking advantage of the benefits available from the use longstem tubestock plants.Although the longstem system was originally proposed as a means of achieving the same deep anchorage as the willow in riparian plantings, a number of additional advantages were subsequently observed.The deep immersion of the root ball has the effect of placing the root structure below the hot, dry strata existing in the immediate surface area of the soil. This condition often prevails on the exposed stream bank and is damaging to surface planted standard tubestock but not to the deep planted longstem tubestock..The deep immersion also places the root system below the region of weed competition and allows accelerated growth compared with the alternative planting procedures. This also reduces the need for weed maintenance in the early growing stage often a major cost with conventional surface planting procedures. Although being the original stimulus driving the development of the deep planting Longstem technology, it very quickly became apparent that the advantages accruing from deep planting along stream-banks and adjacent flood planes could be applied to many other revegetation situations.The use of more mature tubestock plants and the moving of the plant rootball to a more hospitable submerged soil environment, it was then presumed, would provide an enhanced survival prospect across the board. Although the use of longstem tubestock in riparian situations is still the principal application, their use in the wider vegetation endeavours is expanding rapidly.Longstems are now also being used for non riparian arid region plantings and for use in the planting of areas affected by a high salinity level. In the latter application the plants employed do need, of course, to be salt tolerant, however the deep submerging of the root ball protects it from being “cooked” by the hot surface layer of salt, often fatal in conventional tubestock plantings.The deep planting of longstem plants has also been found to be particularly effective in sand dune stabilisation. Again in this instance, as is the case with arid region planting, the root ball is well below the often extremely hot top layers of sand or arid soil and has available to it at least some degree of moisture present in the deeper zone.Bush-care and road-side tree planting programs have also benefited from the use of longstem tubestock in achieving far greater survival results. One unexpected benefit has been the reduced loss from vandalism as it is much more difficult to pull out a deeply planted root ball.Re-establishment of vegetation in degraded rainforests has always presented a major challenge due to the absence of the normal canopy present in the original rainforest environment. In the natural rainforestseedling situation plants experience significant shading and protection from harsh sunlight for quite a few years. As the soil of rainforests is usually very open and subject to drying out, the juvenile plants find it difficult to survive if the protective canopy is not present. The use of longstem tubestock and the deep submerging of the root ball provides this protection in an artificial way and has been the difference between success and failure in rainforest restoration.Another benefit observed from the use of longstem tubestock has been the better response to frost damage. Much of the loss from frost is due, not only to the freezing of the plant superstructure, but also destruction of the root system adjacent to the frozen soil surface. With longstem tubestock the root is well below the frozen frost line. Although the above ground portion of the plant may be destroyed, the still viable root structure can in many instances re-shoot the following spring and have a good chance of surviving the following winters.In many cases surviving the first winter also has the effect of increasing the plants ongoing resistance to frost.Although developed using Australian native plants, the longstem technology is equally applicable to plants from other regions of the world and it is now being used in areas outside of Australia employing plants indigenous to those particular environments.It should be born in mind that the longstem technology does not give the plant any magical power to overcome all obstacles. The plants selected should be appropriate to the area in which they are to be planted and preferably of local provenance. They also need to be appropriate to the soil environment in which they are to be planted e.g. wet, dry, clay, friable, sandy etc. All of these soil conditions can exist within a particular provenance and should be recognised before the species is selected, even though they may be provenance acceptable.If plants are being purchased, search for a reliable nursery which understands the importance of provenance planting and obtain their assurance that their seed supplier knows accurately the source of the seed.In some situations where the ground environment has been severely damaged or degraded or where a canopy is necessary during the early growing period, it may be necessary to substitute non provenance species to provide a quick canopy, The provenance species can then be planted at an appropriate later date and after they have developed successfully cut out the earlier canopy plantings if desired.In regard to the suitability of a plant for longstem development and planting, it would appear that most, if not all, hard tissue plants exhibit a satisfactory response to containment within a small forestry type tube, i.e. healthy growth and undistorted root development. This also applies to the question of deep planting. It is of course assumed that they are grown with the appropriate elevated levels of fertiliser and micro nutrients.If the plants are to be grown in a small in-house community nursery and seed is to be collected by the group then the same aspect of local provenance requirement applies to seed acquisition as it does for purchased longstem plants. However collection of seed is not an easy project with many species. Difficulties such as the physical disability of the collector, seasonal seed bearing variability and the absolute impossibility of collecting seed from some species, particularly very tall eucalypts, without mechanical aids.However there are many reliable seed providers who will service the appropriate seed requirement for longstem tubestock production and with guaranteed advice on the source of collection.It is not possible to provide a list of trees that have a proven record in longstem tubestock application. As the longstem tubestock technique has now been used right across Australia for quite a few years the list would be very extensive and most likely incomplete. As was mentioned earlier, it can be assumed that almost all, if not all, hard tissue trees and shrubs will beneficially adapt to longstem growing and deep planting.Some plants however require a somewhat longer time than others to reach the required planting length. Growing periods with most species vary between ten to fifteen months. Some, particularly rainforest species may take up to twenty four months to reach that requirement.The most immediate outcome from the development of the longstem technology is that there need never be another willow planted along Australia’s rivers and streams and that plant survival rates in all forms of vegetation programs will be considerably enhanced.

Entering “longstem tubestock” into Google and other search engines will reveal a wealth of additional information regarding the application of longstem planting techniques across Australia and across the world.